A faulty Oxygen Sensor is a primary reason for Failure of a Catalytic Converter. Car Manufacturers Recommend Replacement of O2 Sensors at 60,000 miles. If you are purchasing a New Catalytic Converter be sure the Oxygen Sensors are Checked and Operating Correctly!
SIERRA WITH 5.3L FLEX Y PIPE ASSEMBLY INCLUDES BOTH CONVERTERS CLASSIC MODEL ONLY TEST GROUP 7GMXT05.3373 LEV LEV2 OR 7GMXT05.3384 LEV LEV2 OR 7GMXT05.3386 LEV LEV2 CA OR NY APPROVED - CARB COMPLIANT D193-120 PER CALIFORNIA AN